Belts for transmitting power in continuously variable transmissions, for example, use laminated rings of metal to bundle a plurality of elements that are arrayed in an annular endless pattern. Metal rings that make up the laminated rings are produced by slicing, at certain axially spaced intervals, a cylindrical drum into endless strips, loading the endless strips into a rolling mill or a circumferential length correcting machine, and processing the loaded endless strips into metal rings having desired circumferential lengths.
Such a rolling mill or a circumferential length correcting machine has a pair of support rollers for supporting a metal ring in a substantially elliptical shape, and a support roller moving means for moving at least one of the support rollers away from the other support roller to impart a prescribed tension to the metal ring. The rolling mill or the circumferential length correcting machine processes the metal ring that is supported in the substantially elliptical shape.
For loading a metal ring into the rolling mill or the circumferential length correcting machine, it has heretofore been customary for the worker to manually deform the metal ring into a substantially elliptical shape that corresponds to a supporting shape provided by the support rollers, and at the same time to manually support the deformed metal ring onto the support rollers. For unloading the metal ring from the rolling mill or the circumferential length correcting machine, it has also been customary for the worker to manually remove the metal ring from the support rollers after the metal ring has been released from the stretched state by reducing the distance between the support rollers with the support roller moving means.
However, the conventional process has been low in efficiency because the metal ring needs to be manually loaded and unloaded each time it is processed by the rolling mill or the circumferential length correcting machine.
Furthermore, since a metal ring is resilient, it is difficult to keep the metal ring in a substantially elliptical shape that corresponds to a supporting shape provided by the support rollers when the metal ring is to be supported on the support rollers. When the metal ring is removed from the support rollers, inasmuch as the metal ring is no longer stretched by the support rollers, the metal ring abruptly recovers its original substantially circular shape from the substantially elliptical shape. At this time, the metal ring tends to contact other members and be damaged thereby. For the above reasons, it has been highly tedious and time-consuming to load metal rings into and unload metal rings from the rolling mill or the circumferential length correcting machine.
It is therefore an object of the present invention to provide an apparatus for loading and unloading a metal ring quickly and highly accurately with increased efficiency.